If you’re interested in composting and compost worms, you may have realized that compost worms aren’t ordinary earthworms – so digging up a handful of these and adding them to the composter is not a particularly good way to get good compost, or happy worms.
Having the right worms can help your compost to break down quickly and efficiently.
The resulting waste product is called a casting, and these are very useful to gardeners because they are full of nutrients such as phosphorus and potassium, and also have microbes that are beneficial to the plants.
In short, you need worms in your compost – but what kind of worms do you want?
When it comes to composting, the kind of worm you have does make a significant difference, and many kinds aren’t really suitable for composting at all.
We are going to look at five types of composting worms. Many worms are known by multiple names, which can cause confusion, so hopefully, this guide will help.
Red Wigglers (Eisenia Fetida)
They sound cute, and they are a great worm to have in your compost pile. They don’t occur in normal garden soil, but do turn up in “natural” compost heaps, such as rotting logs.
They are thin, dark red worms, usually slimmer and flatter than your common garden earthworm, and they tend to have yellow stripes banding around the body.
They are also sometimes called tiger worms, for obvious reasons!
Red wigglers reproduce quickly and are tolerant of quite a wide temperature range (55-95°F), so they are considered an ideal worm for composting. They measure around 2-4 inches.
They are usually among the cheapest composting worms you can purchase, which also makes them a good option for beginner compost-fans.
Other names include:
- manure worm
- tiger worm
- brandling worm
- troutfish worm
- panfish worm
Redworms (Lumbricus Rubellus)
The other kind of worm that is very good for compost, redworms again tend to be a little flatter than earthworms, and have a distinctly reddish tint to them. They may have a somewhat yellow underside.
They are fairly temperature hardy, and will survive cold winters without a problem. They generally measure between 1-4 inches.
Redworms look similar to red wigglers, and many people feel that they have similar advantages, so you can use either in your compost bin, although red wigglers seem to be the favorites.
Like the red wigglers, these tend to be good worms for any kind of composting conditions (within reason).
They will survive temperature fluctuations and are tolerant of less-than-ideal environments, at least most of the time. For your first foray into composting, they make a good option.
Other names include:
- red earthworm
European Nightcrawler (Eisenia Hortensis)
It might sound like something from a horror movie, but this is another popular composting worm. It’s related to the red wiggler, and is larger.
It is an efficient composter and would make a good addition to your compost bin, but it does have some disadvantages when compared to its smaller cousin.
It prefers slightly cooler temperatures. If you’re operating your compost bin at a high temperature to maximize its efficiency, you may find that this worm isn’t super happy.
It also doesn’t reproduce as fast, so you may find that it takes a while for them to really get going in your compost bin.
However, this worm is often used in fishing, so you may find them a little easier to source, especially if you have a fishing shop nearby and you don’t want to shop online.
They generally live a little deeper down in the compost bin, so you are less likely to see them than the first two options.
These worms take about 20 weeks to reach sexual maturity, at which point they will start breeding.
African Nightcrawler (Eudrilus Eugeniae)
These worms are long and thin, and are considered particularly good for composting, though they do have a downside too.
They are fast to reproduce because they mature quickly, reaching sexual maturity in just 35 days in optimal conditions.
They are usually even faster than the red wiggler, which means they are a popular choice with many composters.
They can measure up to 12 inches when fully grown (or longer!), though they tend to stay thin.
They break food down very fast. They can eat more than their body weight in a day if they are kept in optimal conditions, and they produce lots of castings for gardeners to use.
If you have a lot of food waste, these are ideal.
So, what’s the caveat? Unfortunately, there is one: African Nightcrawlers don’t tolerate the cold well. That makes them unsuitable for outdoor composting in any cool environment, especially during the winter.
They will simply die off if temperatures within the compost heap get much lower than 60°F, while other worms are much more tolerant of low temperatures.
African Nightcrawlers can still be a good option for an indoor wormery or outdoor composting if you are able to ensure a steady temperature, but if it gets cold, you may find that they all simply die.
Indian Blue (Perionyx Excavatus)
These look similar to red wigglers, and they are great composting worms, but like the African Nightcrawler, they prefer warm, tropical environments, and will struggle if the temperature drops significantly.
These are a less common kind of composting worm, so you may find it harder to source them if you decide you’d like to add them to your composting efforts.
Indian blue worms tend to be quick to reproduce, so they can quickly fill a compost bin or wormery. They are smaller than the African Nightcrawler, but similar in color and iridescent in the light.
Most will survive a temperature drop for a few days, but sustained periods of time in temperatures below 70°F may kill them.
Remember, however, that the air temperature doesn’t dictate the actual temperature inside your compost heap; it should be warmer in there.
The biggest problem with Indian blue worms is that they tend to relocate if they are unhappy with the conditions. All worms will do this to some extent, but Indian blues are famous for it.
They are sensitive to atmospheric pressures, and if there’s a thunderstorm, they may decide to move elsewhere.
This makes Indian blues a poor choice for an indoor wormery, as you may find they keep trying to leave if the conditions aren’t quite right for them.
Coupled with their dislike for low temperatures, this means they are a worm you can only use if you have the right conditions for them.
However, they do tend to be a lot cheaper, although harder to source.
They aren’t suitable as a fishing worm, and because they are less popular than compost worms such as red wigglers, they don’t tend to be sold in as many places, even online.
How Do I Keep Worms Happy?
Now we’ve talked about all the different kinds of composting worms, you might be interested to know more about their requirements and what you have to do to ensure your worms survive.
Despite the differences between the worms, they all need fairly similar conditions, so here’s how you keep your worms happy and healthy.
The temperature tolerance variation is the biggest one to watch out for; otherwise, most requirements will be the same regardless of what kind of worms you have.
- A moist but not wet environment. If you squeeze a handful of compost, you should get a few drops of water. Think of a wrung-out sponge.
- If too much water comes out, you need to add dry ingredients; if no water comes out, it’s time to add some wet food scraps such as melon or cabbage.
- Air circulation. This shouldn’t be a problem outdoors, but if you’re composting inside, remember that you can’t keep worms in an airtight container. They will suffocate.
- Food: worms must eat, and after all, that’s what you want them in your compost for – to help digest and break down the food. Make sure your worms have plenty to eat, especially if you compost indoors and you’re going away for a while.
- Carbon: worms need carbon in their food, so make sure you are providing some shredded paper or cardboard along with your fruit and veggie scraps.
Is There Anything Worms Can’t Eat?
What should you not add to your compost pile if you want to keep your little wriggly friends happy?
Worms are pretty versatile, and will pick around and avoid foods they don’t like (provided they have enough space to do so; it is harder for them to do this in a wormery).
However, they are not overly fond of strong foods like citrus fruits and onion peelings. They may also struggle to deal with meat, dairy, and lots of fat.
If you’re composting indoors and consequently in a small space, avoid adding these things.
Outdoors, small quantities won’t hurt and will gradually get broken down, but you’ll probably find the worms go for other food options before eating these, and they may avoid them entirely.
Meat and dairy should particularly be avoided when indoor composting, as they can go off, attract flies, end up full of maggots, and smell terrible.
Your worms won’t particularly care, but this is not something anyone wants in their kitchen!
Which Worms Aren’t Good For Composting?
Some types of worms, it may surprise you to learn, aren’t suitable for composting at all – even though they do break down organic material.
Anecic worms are a group of strong worms that burrow both vertically and horizontally, and they are not suitable for composting because they don’t feed at the surface.
They like to take organic material deep into the earth, sometimes as far as nine feet down, so they won’t do for a compost pile.
This group includes common nightcrawlers and they are usually used as fishing bait. They aerate the soil and are very good for your garden – just not directly for your compost heap.
Endogeic worms do not go as deep as anecic worms and they tend not to make such large, stable burrows, but they are also not suitable for use in composters.
Again, they don’t feed at the surface, but tend to drag food down below ground.
Finally, the group that is suitable is called epigeic, and these worms live in the surface soil.
They can’t cope with the compressed soil further down, and tend to feed on any nutrient-rich food they find at surface level. All the worms listed above are epigeic.
How Do I Get Worms?
If you are just starting either a compost bin or a wormery, you need worms (especially for the latter).
Outdoors, you may find that the right kind of worm naturally makes its way to your compost heap, but this will take time. Indoors, obviously, it is very unlikely to happen.
The answer is that you should buy some worms, or ask a friend who has a compost bin – they are likely to spare you a good handful, as most worms are quick to reproduce and will make up the deficit numbers very fast.
If you need to buy some, try to learn a bit more about them before you buy.
Many worms look extremely similar, and you may end up with Indian blues when you wanted red wrigglers – so inspect the worms carefully if possible.
If purchasing online, choose a seller who offers lots of information and has positive feedback to ensure the best experience.
Set up your bin or compost heap in advance, and put your worms in!
Now that you know what kinds of worms are suitable for composting, you can decide which ones would be suitable for you too.
Some worms will coexist, especially outdoors, but it’s generally better to just have one species in your compost, as multiple ones can cause issues and drive each other out.
Select your worms based on your individual needs, and don’t use Indian blues indoors, unless you aren’t too worried about them escaping from time to time!
Remember that any kind of worm will try to leave a place that does not meet their needs, so if your worms are consistently crawling away, look at what might be wrong, and rectify the issue.